[0001] This invention relates to a press apparatus for charging a flowable material into
selected cells of a honeycomb structure and, more particularly, to a press apparatus
for use in selectively manifolding (i.e. plugging) cells of a honeycomb structure
for the fabrication of filter bodies and other manifolded honeycomb structures.
[0002] Honeycomb structures having transverse cross-sectional cellular densities of from
one-tenth to one hundred or more cells per square centimetre, especially when formed
from ceramic materials, have several uses, including solid particulate filter bodies
and stationary heat exchangers, which require selected cells of the structure to be
sealed by manifolding or other means at one or both of their ends.-The term "seal"
and its corresponding grammatical and derivative forms (i.e. "sealed", "sealant",
"sealing", etc) are used herein to refer to both porous and non-porous closing and
means of closing the open transverse cross-sectional areas of the cells of honeycomb
structures.
[0003] It is well known that a solid particulate filter body may be fabricated utilizing
a honeycomb structure formed by a matrix of intersecting, thin, porous walls which
extend across and between two of its opposing end faces and from a large number of
adjoining hollow passages or cells which also extend between and are open at the end
faces of the structure. To form a filter, one end of each of the cells is sealed,
a first subset of cells being sealed at one end face and the remaining cells being
sealed at the remaining opposing end face of the structure. The contamination fluid
is brought under pressure to one face ("inlet" face) and enters the filter bodies
via the cells which are open at the inlet face ("inlet" cells). Because the inlet
cells are sealed at the remaining ("outlet") end face of the body, the contaminated
fluid is forced through the thin, porous walls into adjoining cells which are sealed
at the inlet face and open at the outlet end face of the filter body ("outlet" cells).
The solid particulate contaminant in the fluid which is too large to pass through
the porous openings in the walls is left behind and a now cleansed fluid exits the
filter body through the outlet cells for use.
[0004] EP-A-0070203, from which the present application is divided, describes and claims
a method of charging flowable material through openings into ends of a selected plurality.of
cells of a honeycomb structure, and a tool for use in forming the said openings. Attention
is directed to EP-A-0070203 for further details. The present invention relates to
a press apparatus which may be used, for example, in carrying out the charging.
[0005] According to the present invention there is provided a press apparatus for charging
a flowable material into a honeycomb structure having a plurality of cells open at
an end face thereof, comprising a press head having a chamber which is open at an
outer surface of the press head to accept said honeycomb structure for charging, and
further having a bore extending away from said chamber opposite said opening; means
for securing said end face of said honeycomb structure across said opening; means
for injecting said flowable material through said press head into said chamber; piston
means slidably mounted in said bore for pressing said flowable material in said chamber
into the end face of said structure; and a flexible diaphragm affixed at its outer
edges to said press head and at its centre to said piston means.
[0006] The press head may also be provided with a flexible, pneumatically operated collar
for securing the honeycomb structure in place during the pressing operation and a
pair of press heads may be provided so that both ends of the honeycomb structure may
be filled in a single operation.
[0007] In the accompanying drawings:
Fig. 1 depicts schematically, in partially sectioned profile, a preferred embodiment
of press apparatus for bulk charging sealing material through openings in a covering
adhered to a honeycomb structure;
Fig. 2 depicts schematically in a sectioned, profile view a press head of the apparatus
of Fig. 1;
Fig. 2a shows the press head of Fig. 2 in -the advanced position; and
Fig. 3 is a schematic sectioned profile view of the press head of Figs. 2 and 2a being
used with a flexible mask.
Fig. 1 shows a preferred, double headed cement press 70 which comprises a frame 71
and upper and lower cement heads 72 and 73. The lower head 73 is fixed to the frame
71. The upper head 72 is adjustable in height above the lower cement head 73 by means
of a screw 74 turning appropriate mechanical linkages such as a rack and pinion (not
depicted) between the frame 71 and upper cement head 72 to accommodate honeycomb structures
21 of various heights. The cement heads 72 and 73 are identical in construction and
the upper head 72 has been sectioned to reveal its major components. A press head
75, depicted in greater detail in Figs. 2, 2a and 3 is provided for pressing a ceramic
cement or other plastically formable material into the honeycomb structure 21. The
press head 75 is affixed by suitable means 76 such as a metal collar to a first air
cylinder 77. A plunger 78 is advanced towards the press head 75 by the operation of
the cylinder 77 to advance a piston 83 in the press head 75 (see Figs. 2, 2a and 3)
by means of a connecting shaft 94 of the piston 83 charging the plastically formable
cement into the honeycomb structure 21. The press head 75, plunger 78 and first air
cylinder 77 can be raised for the insertion or removal of the honeycomb structure
21 by operation of a suitable device such as a second air cylinder 80 and a second
plunger 79 extending from the second cylinder 80 and connected to the first cylinder
77. A mechanical jaw 81 or similar device may be provided to automatically insert
and remove the honeycomb structure 21 from the press 70. Means such as cement feed
tubes 82 are provided to carry cement to the press heads 75 for charging into the
structure 21.
[0008] Figs. 2 and 2a depict a sectioned press head 75 with its piston 83 in retracted and
advanced positions, respectively, and a partially sectioned honeycomb structure 21
having an end face covered with a thin film covering 28. Openings 29 have been formed
through the film covering 28 over alternate cell ends in the manner previously described.
The end face of the honeycomb structure is held in position across a feed chamber
84 in the press head by means of a pneumatically inflated collar 85 affixed to the
press head and surrounding the side walls of the structure 21 near its end face. The
collar may be simply a flexible, inflatable tube,-or more desirably, may be such a
tube fitted with a protective covering around its inner periphery such as a split
ring metal collar (not depicted) which may be compressed around the side walls of
the structure 21 to grip the structure better and prevent wear of the tube. The ceramic
cement is carried to the press head 75 through the feed tube 82 and injected into
the chamber 84 through suitable means such as from'a first hollow annular ring 86
formed in the press head 75 through a concentric annular passage 88 also formed in
the head 75 which is open at its outer circumference to the ring 86 and at its inner
circumference to the chamber 84. It is also envisaged that the cement may be injected
into the chamber 84 by means of a bore axially through the piston 83. After charging
the chamber 84 with cement, the piston 83 is advanced by activation of the first air
cylinder 77 which extends the first plunger 78 in the direction indicated by the arrow
92. The plunger 78 strikes a connecting shaft 94 of piston 83, advancing the piston
83 in the same direction 92 which presses the cement in the chamber 84 through the
openings 29 into the alternate cell ends forming plugs 40 as depicted in Fig. 2a.
The piston 83 is then retracted in the direction indicated by the arrow 93 by suitable
means such as a compression spring 91 around the connecting shaft 94 of the piston
83. A flexible annular gasket 89 is also affixed near the head of the piston 83 and
to the body of the press head 75 to prevent blowby of the cement into the piston bore.
The piston 83 is formed from several joined segments, as indicated, to allow insertion
of the gasket 89. The head of the piston 83 is smaller than its body to provide sufficient
space for movement of the gasket 89. A Bellofram (Trade Mark) diaphragm which is formed
from a butyl rubber impregnated nylon fabric has been found sufficiently durable for
use as the flexible gasket 89. If desired the surface 90 of the piston head 83 facing
the chamber 84 may be coated with a neoprene rubber or other soft resilient material
to prevent possible damage to the honeycomb structure 21 when the piston head 83 is
advanced. It is also envisaged that the press 70 may also be used with a flexible
mask 99 as is depicted in Fig. 3. The mask 99 is described in EP-A-70671, filed 13th
July 1982, published 26th January 1983, and claiming three priorities respectively
of 15th July 1981, 15th July 1981 and 24th August 1981.
1. A press apparatus (70) for charging a flowable material into a honeycomb structure
(21) having a plurality of cells open at an end face thereof, comprising a press head
(75) having a chamber (84) which is open at an outer surface of the press head to
accept said honeycomb structure (21) for charging, and further having a bore extending
away from said chamber (84) opposite said opening; means (85) for securing said end
face of said honeycomb structure (21) across said opening; means (82) for injecting
said flowable material through said press head (75) into said chamber (84); piston
means (83) slidably mounted in said bore for pressing said flowable material in said
chamber (84) into the end face of said structure (21); and a flexible diaphragm (89)
affixed at its outer edges to said press head (75) and at its centre to said piston
means (83).
2. An apparatus according to claim 1, wherein said means for securing comprises a
pneumatically inflated collar (85) affixed to said press head (75).
3. An apparatus according to claim 1 or 2, further comprising a frame (71) on which
said first press head (75) is fixedly mounted; a second press head (75); and means
for adjustably mounting said second press head (75) to said frame (71) for movement
with respect to said fixedly mounted press head (75), whereby both end faces of a
honeycomb structure (21) may be charged at the same time with said flowable material.
